Annoying problems at common aperture settings (and how to solve them)

Problems with middle aperture settings

SUBJECT NOT ISOLATED FROM BACKGROUND
Mid-range aperture settings such as f/8 and f/11 are often a great choice because they usually get the best out of a lens, producing sharper results than shooting wide open and avoiding problematic diffraction associated with very small apertures.

However, depth of field is greater than when using larger aperture settings and this can mean that the subject is not sufficiently isolated from the background.

Solution
Depth of field generally extends twice as far behind the point of focus as it does in front, so try to make the most of the depth of field that a mid-range aperture setting gives you and focus towards the front of the subject.

If you are photographing a group of people, for example, don’t focus on the back row, focus on the front row – or a row near the front.

NOT ENOUGH DEPTH OF FIELD
Although using a middle aperture setting ensures the focal point of your image is nice and sharp, there may not be sufficient depth of field to get it all sharp. This a particular problem when shooting close-up and macro subjects, but it can also be an issue with landscapes.

Solution
A relatively simple solution with static subjects is to take a series of images, each one with the focus set to a different distance into the scene.

Take the first shot with the nearest part of the scene in focus, then refocus just a little further into the scene and take the second shot before focusing further in again.

Repeat this until you have shot with the focus on the furthest part of the scene.

Now all the shots can be combined to create one image that is sharp throughout. This can be done manually using any image editing software that supports layers – Photoshop Elements is fine.

But it can also be done automatically using Combine ZM, which is free to download and use, or using Photoshop’s Photo Merge function.